The tasks to utilize this contract are to analyze samples from the Calcium for Preeclampsia Prevention trial (CPEP) to measure total 25(0H)D, its isoforms (25(0H)D2 and 25(0H)D3), Vitamin D binding protein (VDBP), albumin, and total calcium in up to 992 serum samples from the CPEP trial. Period of performance for this task is estimated to be 6 months. The Division of lntramural Population Health Research of the Eunice Kennedy Shriver National Institute of Child Health and Human Development encompasses three branches: 1) Epidemiology Branch; 2) Biostatistics and Bioinformatics Branch and 3) Prevention Research Branch [http://www.nichd.nih.gov/about/org/despr/]. Central to the Division's mission is to design, implement, and direct epidemiologic, behavioral and biostatistical research which focuses on reproductive, perinatal and pediatric epidemiologic research as well as research addressing child and adolescent health behaviors. The Division previously conducted the Calcium for Preeclampsia Prevention (CPEP) trial from 1992-1995 across 5 clinics in the US testing the effect of calcium supplementation on risk and severity of preeclampsia (PE). One of the CPEP study sites (Memphis, TN) conducted an ancillary study of' Fetal bone mineralization' whereby both the mother and her newborn could receive a dual-energy X-ray absorptiometry (DXA) scan. Several studies have shown that . women with vitamin D deficiency during pregnancy tend to have infants with lower birth weight, although the evidence is still controversial. To build on previous findings, we will measure maternal CPEP serum samples for vitamin D biomarkers to investigate maternal vitamin D status in association with neonatal body fat and neonatal bone mineral content. Maternal vitamin D status will also be examined in association with maternal bone mineral content. Serum samples collected longitudinally in this trial will offer several measures of vitamin D status throughout gestation enabling us to better characterize the vitamin D profile of these women. These measures will also be used to characterize the trajectories of vitamin D biomarkers across gestation stratifying by two racial groups namely Whites and African-Americans. Serum samples from the trial have been stored in the NICHD Bio-repository at -70C. Aliquots of the participants will be shipped to the laboratory